Natural gas combined power generation process with zero carbon emission

A natural gas combined power generation process with zero carbon emission, the process comprising:

• 1) pressurizing air with an air compressor to a pressure of 0.4˜0.8 MPa, and then introducing the pressurized air into an air separation facility for performing air separation to obtain liquid oxygen and liquid nitrogen;
• 2) performing heat exchange at a cooler between the liquid oxygen and a high-temperature CO2 at an outlet of a supercritical CO2 generator, so as to generate high-pressure vaporized oxygen and recyclable CO2;
• 3) combusting the high-pressure vaporized oxygen and natural gas, and obtained high-temperature combustion flue gas drives the air compressor and a generator to generate electricity;
• 4) subjecting the high-temperature combustion flue gas obtained in step 3) to a heat exchange in a CO2 waste heat boiler to perform a supercritical CO2 power generation;
• 5) performing heat exchange of the heat exchanged combustion flue gas obtained in step 4) with liquid nitrogen through a vaporizer to obtain a stepwise cooled flue gas, and the vaporization of liquid nitrogen drives a nitrogen turbine generator to generate electricity.